Before knowing what Creatine does, it is of vital importance to first know what it is. Creatine is an amino acid that occurs naturally in the body and is found in the kidney and liver. It provides energy to cells by creating adenosine triphosphate, or ATP. Most of the cells that creatine supplies energy to are muscle cells, and it fuels muscle contractions. Creatine as a supplement essentially does the same thing as the natural amino acid, just in larger quantities. For example, the body typically produces about 2-3 grams of the amino acid per day, while man-made supplements include daily consumption of about 15-25 grams of the substance. Because of its similarity to whey protein, many false protein supplements feature creatine as a main ingredient. Creatine is, in short, a natural amino acid that fuels muscle contractions and can also be synthetic and taken as a workout supplement.